Formation of a synovial-like membrane at the bone-cement interface. Its role in bone resorption and implant loosening after total hip replacement.

Histologic evaluation of tissue surrounding the loosened components after joint replacement reveals the presence of a synovial-like lining adjacent to the polymethyl methacrylate cement. The tissue is heavily infiltrated with particulate cement as well as polyethylene associated with a foreign body-type giant cell reaction. That this tissue response may be responsible for the bone lysis associated with loosening is suggested by the demonstration of high prostaglandin E2 levels and enhanced bone resorbing activity in the tissue culture medium of fragments from this membrane.